The present invention relates to improvements in power transmitting apparatus, and more particularly to improvements in power transmitting apparatus of the type employing fluid couplings such as Föttinger couplings, hydrodynamic torque converters or analogous machines. Still more particularly, the invention relates to improvements in apparatus wherein a rotary housing can be driven by the output device of a prime mover (e.g., by the crankshaft of a combustion engine in a motor vehicle) to transmit torque to an input device (e.g., to the input shaft of a variable speed transmission in the power train between the engine and one or more wheels of a motor vehicle). As a rule, the housing in an apparatus of the above outlined character confines and transmits torque to an impeller, and the input device receives torque from a runner which is also installed in the housing. A guide wheel is or can be provided in the housing to operate between the impeller and the runner, and at least one torsionally elastic damper is or can be installed in the path for the flow of power between the housing and the input device, e.g., between the housing and a hub which can be used to drive the input shaft of the aforementioned transmission. In many instances, the damper comprises one or more energy storing elements and the apparatus can also comprise a so-called bypass clutch which serves to establish a direct connection between the housing and the output device, i.e., between the output device of the prime mover and the driven unit (such as a transmission) and to thus bypass the fluid coupling.